West Yorkshire Police have said that five people are being held in custody over the stabbing of a nine-year-old boy, an eight-year-old girl being chased through her home and the fatal stabbing of an elderly lady which they believe are all linked.

Speaking at the skate park where the boy was attacked on Monday, Detective Superintendent Lisa Griffin said the boy was stabbed in a random attack.

The officer said a girl was chased through her garden 10 minutes after the attack on the boy yesterday afternoon.

Ms Griffin confirmed that a knife had been recovered and that a 26-year-old man arrested on suspicion of murder and attempted murder was related to Mrs Denby.

She said: “Ten minutes after that attack on a nine-year-old boy, an eight-year-old girl was chased through her garden at home.

“Fortunately the girl went inside the house and nothing untoward happened to her.”

“I make that assertion on the basis that the description of the suspect tallies with the two incidents involving the children.

“We've made that link and we're appealing to the public to give us information about the person responsible.

Ms Griffin said: “The nine-year-old boy was out playing and was returning home for a drink when he was approached by the male suspect and, with no prior warning and for no reason known to us at this time, he was attacked with a knife - a single stab wound causing him injuries to his chest and his arm.”

The boy was taken to Leeds General Infirmary after emergency services were called to the skate park at about 4.40pm yesterday. He was due to undergo surgery today and is described as being in a stable condition.

The detective said the girl was playing in her garden when a male approached and tried to draw her attention and chased her through the garden and she went inside.

She said no contact was made with the girl and no weapon was seen.

Ms Griffin said: “I would still encourage the public to make any call to us if they can possibly assist with further information about the male who we believe is responsible for the attack on the nine-year-old boy and the murder of the 84-year-old lady.”

She said police and forensics officers were working on ten different scenes in the area.

Mrs Denby's body was found just before midnight last night. She had suffered a number of stab wounds.

The pensioner's next-door neighbour, Jackie Smith, paid tribute to the retired teacher today, saying she was a friend and a “lovely lady”.

“She was such a good neighbour and she was really respected down this road,” she said speaking outside her home.

Police have said the 26-year-old man now in custody was spotted by a member of the public in Westfield Lane, Idle, Bradford, at 4.10am today and detained by officers.

The police spokesman said another 26-year-old man has also been arrested in connection with the murder.

Three other local men - aged 18, 24 and 29 - have been arrested over the incident in the skate park, he added.